Method and apparatus for liquid treatment



July 15, 1952 J. M. DAILY 2,603,597

METHOD AND APPARATUS FOR LIQUID TREATMENT Filed Nov. 6, 1946 Patented July 15, 1952 7' METHOD AND APPARATUS FOB/LIQUID TREATMENT James M. Daily, Wilmette, 111., assignor to American Ozone Company, Chicago, 111.-

Application November 6, 1946, Serial No. 708,201

14 Claims.

The present invention relates generally to the treatment, clarification and purification of polluted liquids with particles suspended therein, such, for example, as sewage and industrial waste. More particularly the invention relates to that type of liquid treatment, clarification and purification which involves the use of ozonous and electrified air.

One object of the invention is to provide an apparatus for, and a method of, treating, clarifying and purifying polluted liquids of the aforementioned character, which are an improvement upon, and have certain inherent advantages over, the apparatus and method of United States Letters Patent No. 2,320,512, granted to me on June 1, 1943, and are characterized by extremely high efiiciency and the fact that they are capable of producing extremely satisfactory results .at a comparatively low cost and with but a comparatively small amount of equipment.

Another object of the invention is to provide an apparatus and method of the last mentioned character which involve as a coagulating and fiocculating medium for the suspended particles in the liquid being treated, an ozonated and acidified solution of ferrous sulfate or like metallic salts capable of coagulating and flocculating aqueous suspended particles, either alone or in combination with part of the recovered sludge or other suspended matter.

A further object of the invention is toprovide an apparatus and method of the aforementioned type and. character which contemplate and involve, as successive operating steps, first mixing with the liquid to be treated the coagulating and fiocculating medium, then removing from the liquid the coagulated and fiocculated substances, then subjecting the liquid to treatment by ozonous andelectrified air in order to reactivate .through oxidation the residual dissolved coagulating and flocculating medium and thus effect further or additional coagulation and flocculation of substantially all remaining suspended particles in the liquid, and then removing from the liquid the coagulated and flocculated substances resulting from such treatment of the liquid by ozonous and electrified air.

A still further object of the invention is to provide an apparatus for, and method of, treating, clarifying and purifying polluted liquids, which are generally an improvement in the art and are characterized by simplicity as well as high efiiciency. I I Other objects of the invention and the various I advantages and characteristics of the present apparatus and method will be apparent from consideration of the following detailed description.

The invention consists in'theseveral novel features which arehereinafter set forth and are more particularly defined by'claims at the conclusion hereof.

In the drawing which accompanies and forms a part of this specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a diagrammatic or schematic plan view of an apparatus embodying the invention; and

Figure 2 is a vertical longitudinal section of the apparatus.

, The apparatus which is shown in the drawing constitutes a part of the present invention and the use thereof involves the method constituting another part of the invention. So far as the method is concerned it may, however, be carried out in an apparatus other than that herein disclosed and illustrated; The apparatus is essentially for the purpose of treating, clarifying and purifying a polluted liquid having suspended particles therein, such, for example, as sewage or I materials forming the fiocculating and coagulating'medium will, for convenience, be referred to as ferrous sulphate. None of such references is to be taken as limiting the generality of the description of the process or of the means by which the result is accomplished. As here-" inafter described in detail, the sewage is treated in the apparatus while it is in a constantly moving or flowing body. In general the apparatus comprises an influent-duct 5 for the raw sewage, a unit 6 for ridding the raw sewage of any and all floating substances and large objects, a mixing chamber 1, a unit 8 forsupplying the mixing chamber with a coagulating and fiocculating medium, a first flocculator- 9, a settling basin I0, an ozonating tower ll,;a.second fiocculator I2, a second settling basin l3 and an effluent duct 14.

The influent duct 5 has the inlet end thereof connected to the sourceof raw sewage to be treated and serves to supply the sewagein the form of a constantly moving or flowing body to the unit 6..

7 Such unit 6 is connected to the discharge end of the influent duct 5 and comprises a screening, grinding or comminuting arrangement (not shown), or a combination thereof, and serves to remove or disintegrate any and all large sized substances and objects in the sewage. Any suitable conventional unit may be employed in the apparatus for the purpose of ridding the raw sewage of large sized objects therein.

The mixing chamber I is connected to the discharge end of the unit 6 by way of a duct [5 and receives the coagulating and fiocculating medium from the unit 8 by way of a pipe It. It is so arranged and designed that the coagulating and flocculating medium is intimately mixed with the raw sewage preparatory to the sewage entering and flowing through the first fiocculator 9. It is contemplated that the coagulating and fiocculating medium from the unit 8 will be introduced into the mixing chamber 1 in ,the form of a steady stream and at a rate that is determined by measurements based on records of the character of the sewage that is to be treated. The unit 8 serves to produce and supply the coagulating and flocculating medium which, as

heretofore indicated, is'in the form of ozonated and acidified ferrous sulphate or like metallic salt either alone or in combinationwith apart of theremoved sludge. As its principal components or parts the unit 8 comprises an ozonating tank [1, a pipe l8 for delivering the recovered sludge from the bottom of the settling basin IEI into the ozonating tank, a hopper I9 for supplying the ozonating tank I! with ferrous sulphate either in solution or in dry form, a reservoir for supplying sulphuric or other acid into the ozonating tank, an ozone generator 2| for introducing ozone or ozonous and electrified air into the tank l1, and a tank 22 for storing the coagulating and flocculating medium that is prepared in said ozonating tank I1. The tank I! may contain bafiles (not shown) to act upon the flow of the various materials through the tank, in order to increase the effectiveness of the ozonation. The ozonating tank I 1 has an open top and is formed of concrete or other material that is not subject to oxidation. The pipe I8 includes a motor driven pump l8a and a valve 23. When the valve is open while the pump is in operation sludge in wet form is pumped from the bottom of the first settling basin liJ through the pipe l3 and into the ozonating tank IT. The hopper I9 is. preferably located above the ozonating tank I! and is adapted to contain a supply of ferrous sulphate in either solution or dry crystal form. It embodies a discharge channel 24 and this leads to, and communicates with, the upper portion of the interior of the ozonating tank I! and has valve means 24a for controlling the feed of ferrous sulphate solution or crystals from the hopper l9 into the ozonating tank ll. The reservoir 20, like the hopper I9, is preferably located above the ozonating tank I1. It is adapted to contain a column or body of acid and is connected to the ozonating tank I! by a pipe 25, having a control valve 26 therein. When the valve 26 is opened the acid in the reservoir 20 flows by gravity or is otherwise led into the interior of the ozonating tank I1. In preparing the coagulating and flocculating medium, sludge recovered from the first settling basin I0 is led in wet form into the ozonating tank I! and acid from the reservoir 20 and ferrous sulphate (in .dry form or in solution) from the hopper [9 are fed into the ozonatingv tank I1.,

The ferrous sulphate, if in dry form," dissolves 4 in the wet sludge. The amount of ferrous sulphate ordinarily required for the production of an effective coagulating and flocculating medium will fall within a range of 2-00 to 1000 pounds per million gallons of sewage to be treated. The amount of acid will vary with the character of the sewage but will ordinarily fall within arange of 50 to pounds of concentrated sulphuric acid (or its equivalent) per million gallons of sewage to be treated. This aggregate of materials so fed into the ozonating tank I1, consisting of a combination of wet recovered sludge and acidified ferrous sulphate, is treated. with ozonous and electrified air in the ozonating tank I 'l for a period of several hours, i. e., until it is saturated to the greatest practicable extent with ozone. The materials so-described, when so treated, form the coagulating and fiocculating medium that is used in the method or process.

In the alternative, the coagulating and flocculating medium used in the process may'consist of a solution-of ozonated acidified ferrous sulphate without the addition of recovered sludge; Use of recovered sludge as one of the component parts of the coagulating and fiocculating medium effects a measure of economy in the cost of the process by diminishing the amount of ferrous sulphate required, and has the further advantage of decreasing the amount of residual sludge to be disposed of, since'ozonation of the sludge as a part of the coagulating and fiocculating medium oxidizes a portion of the sludge to extinction. Moreover, the ozonation, as pointed out elsewhere herein, is a definite aid in disposing of the residual sludge, by incineration, as itrenders the sludge more readily combustible-than otherwise. The process may, however, be efiectively and economically used when the coagulating and flocculating medium is made up solely of an-ozonated sludge recovered from the first settling basin islead away directly for disposal in its entirety, none of it entering the ozonating tank [1. In such case the slud e that is removed from the first settling basin, instead of being introduced into the ozonating tank i1, is led into a second ozonating tank, (not shown) which is like the ozonating tank I! and functions in the same manner. By ozonating thesludge which is not used to form a component part of the coagulating and flocculating medium a portion of the sludge is consumed by ox'idationand the balance, when dried, may be readily burned because of its high oxygen content. Conversely, the process after being initiated with a coagulating-and fiocculating medium made up of an ozonated combination of acidified ferrous sulphate and recovered sludge, may under some conditions be carried on thereafter by the use of ozonated sludge alone as a coagulating and fiocculating medium, without further addition of ferrous sulphate and the process as hereinafter described is intended to cover that procedure likewise. When the process is being carried on in that alternative manner, the mechanical apparatus here shown is suitable for such operation, and the steps in the operation are the same except for the omission to add in the ozonating tank I1 any additional acidified ferrous sulphate when recovered sludge is -being use as the coagulating to be understood, however, that'any conventional or standard pressure type ozonator may be employed. The generator'2l has associated with it a compressor 21 which serves to supply it with air under-pressure for conversion into ozonous and electrified air. A'pipe 28 receives the'ozonous and electrified air that isproduced in the genera-' tor 2i and serves when thegenerator is in operation to supply such air to diffusers 29 in the bottom portion ofthe ozonating tank IT. The diffusers are formed of porous stone or pipe sections which have minute discharge apertures therein and are formed of any suitable material that/is not subject to oxidation by the ozonous and-electrified air. The capacity of the compressor 21 i such that the ozonous and electrified air emanating from the generator 2| via the pipe 28 is under sufiicient pressure to overcome the weight of the combined materials in the'ozonating tank l1 and also the'resistance incident to the difiusing action of the diffusers 29. When the ozone generator is in operation the ozonous and electrified air flows upwards'throughthe wet combined materials in the ozonating tank I! in the form of small bubbles and reacts both with the ferrous sulphate component and with the recovered sludge component. In practice it has been found thatin the reaction of the ozonous and electrified air with said components best results are obtained when'the material'is acidified, and it is for this reason that the unit 8 includes the reservoir 20 for introducing an acid, such as sulphuric acid, into the materials in the ozonating tank l1. Whereas sulphuric acid is preferably utilized to acidify the material in the mixing tank, it is to be understood that any other suitabe acid, organic or inorganic, or any acid salt may be employed.- In practice, it has been found that desirable results are obtained when the hydrogen ion concentration of the materials in the ozonating tank is adjusted to and maintained at a pH of four to five.

As an alternative procedure, it may sometimes be desirable, as in case of intermittent operation,

or of curtailment of power supply, or for other reasons, to ozonate the acidified ferrous sulphate, in solution, separately from the sludge, and then to mix it with the separately ozonated sludge to form the coagulating and fiocculating'medium that is used in the process. In such case the ozonous and electrified air may be introduced into the ozonating tank either during or after dissolution of the ferrous sulphate in the solution. As soon as the ozonous and'ele'ctrified air is introduced into the ferrous sulphate solution byway of the diifusers 29 the solution foams violently. This 'is attributable to the reaction that occurs between the ozonous and electrified air and the ferrous sulphate solution. As soon as thereaction of such air with the ferrous sulphate is complete, i. e., as soon as the solution is completely'saturated with the ozonous and electrified air, the foam subsides. By noting when the foam subsides the operatorv of the apparatus is visually apprised of the fact that'preparation of the batch of ozonated ferrous sulphate solution is complete. It-is'contemplated that as soon as the operator notes discontinuance of foaming of the solution in the tankthe operation of the ozone generator will be stopped so as to eliminate waste of'o'zonous andelectrified air. It is to be understoodthat this phenomenon does not occur when, as will ordinarily be the case, the ozone is applied to the acidified ferrous sulphate and the sludge in. combination. If the alternative procedure isne'mployed'or u'sedthe acidified ferrous sulphate solution, after being ozonated to the fullestor desired extent, is fed or introduced into the storage tank '22. Thereafter a batch of removed or recovered sludge is introduced into the ozonating tank I! by opening the valve 23 and operating the pump Isa in the pipe [8. After ozonation in thetanks H the batch is fed or introduced into the storage tank 22 where it mixes with the pre-' viously made ozonated and acidified ferrous sulphate solution. The alternative procedure, as

herein indicated is capable of being carried out in the apparatus herein shown and described.

The storage tank 22 is located beneath or adjacent 'the ozonating tank [1 and receives the coagulating and fiocculating medium therefrom by way of a pipe 30 having a control valve 31 therein. The storage tank 22 is sodesigned that the heavier part of the sludge component of the coagulating and flocculating medium so received settles in the bottom of the tanlnfrom whichit is periodically removed by way of a valve controlled drain pipe 22a, without disturbance of the/balance of the contents of the tank. The heavy sludge so removed will have been previously ozonated in the ozonating tank to such extent as to render it sterile and inoffensive, and harmless to plant or aquatic life, so that it may, if desired, be disposed of by dumping in any watercourse without rendering the water offensive or impairing its usefulness. Alternatively, it may be readily disposed of by drying and incineration, as it has been found that such ozonated sludge is combustible to much greater degree than sludge which has not been so treated. Withdrawal from the storage tank 22 of the heavier sludge, as described. leaves in the tank combined or intermixed materials made up of the lighter remaining ozonated sludge and the ozonated and acidified ferrous sulphate solution, which combined materials constitute the coagulating and flocculating medium. In practical operation, the amount of settled sludge which is withdrawn from the storage tank 22 for disposal is a minor part of the total quantity of sludge which is in circulation in the process, the sludge being kept in circulation to the greatest extent feasible inorder to facilitate the rapid formation of a fioc in the first flocculator 9. The quantity of sludg so withdrawn is substantially less than the quantity received when the influent raw sewage, a part of the recovered sludge being ozonated to extinction in the ozonating tank IT. The ipe l6 leads from the storage tank 22 to themixing chamber 1 and includes a motor driven pump 32, The latter when operated serves to supply the coagulating and flocculating medium from the storage tank into the mixing chamber 1. The pump 32 is driven so-that the coagulating and fiocculating medium is introduced into the mixing chamber in a steady stream and at a rate that is determined by measurement based on records of the character of the sewage to be treated. 5

The firstflocculator is associated with, and, in effect, forms'a part of, the first settling basin Hi. It is in the form of a horizontally elongated channel type unit andcomprises-an outer side wall 33, an inner side wall 34, a bottom wall35, a

pair 'ofr end'r walls J36 rand-331.; a seriesllofi bafil 38aandz-a series :of; coacting bafiles 39;: As shown in the drawing the. bafile's 2.8 areaarranged; in :;a1 ternate relations-with the baffles;39-wandeare1laterally .offset.jwith;respect to theilatter; Alternatiye-g 1y; othersmeansthan bafi'iesk'mayqbevused;forigth agitationcffthacontainedasewagei The outerraz z inner lsl'd'e' Wallsr33 and 34:, ;the;bDtl m;Vl 8;113i and :the endwalls; 351and :31 *form: a horizontally elongatedi channel 40: through which-thesewaefi is adapted slowly to; flow. Thesewlage,- after having the: coagulating andfiocculating; medium mixedcwithxit'in themixingrchamber l, f10Ws;intO theireceiving: enclv of thechannel .dflibyr'way of a duct 14-! which extendsbetweengandlis connected to, the mixing chamber and the .:end:wa1lf36=. of the; first fiocoulatorytlf As hereinaftendescribed; thesewage; after flowing through .thenhannelfifi; flows :into :the first, settling basin ;l 0:.- -b'y .way' :of, a dischargeropeningdl whichis formed, in the end of the innerzside wall;34that;:is;adjacent; the end wall3l; .The baflles; as shown inzthe -draw-, ing,j cause the sewagewiththe coagulatingand flocculating medium therein tov flow in a: tortuous or serpentine course. through the; channel; 401111 the first fiocculatorfib During :flOW ofgthe-zsewage through the first: fiocculatorthe coagulatingand fiooculating mediumeffect coagulation and fioccue lation: of the suspended: particlesin thesew'age. This t= coagulating. and flocculating. medium; bee cause; of its impregnation-with; ozone,' alsoxef fects an oxidation of the sewage with resulting reduction in; its; biochemical oxygen demand. During :flow ofthe sewage through the first fioc culatorthere a; definite formation of: afioc structure. Thesewage as it fiowsthroughthe channel 40 is slightly agitated by: thelbafilesor other means iwithrthe result that thereis 'a'.marked or pronounced: tendency ofthe flocstructure :to develop, or grow inv size. Preferably the first flocculator' isof such length that :it 1' takes the sewage. from between -15 i to: 30:minutes (to: flow th'erethrough; If: desired; mechanical means other than the :bafiles :38- and 39. maybeutilized inthe firstfiocculator 9 r to: effect slow agitation of the sewage for the; purpose; of-s developing. or buildingunp therflocistructurerresultingr from contactwof rthe coagulating and flocculatingmedium with the organic '7 and inorganic, suspended' fpar ticles-in thesewagei V Thefirs-t settling basin I9 is positioned-An side by; siderelation with: the first-'fiocculator: Q'iand is horizontally elongated as shown-v in: Figure 1. It comprises: a; sidewall 1'43; and a .a pair "of -"end walls 44 and: Hand 5a downwardly? tapered hopper-like bottom-wall 46 The-,innerside wall 3'4 of thefirstv flocculatorforms the. otherside wall ofsthe first'settlingcbasinr |0.- Thgend 'wall l l adj oinsgand forms a continuationnfithe end wall 31- ofthe first fiocculator. V Theldis'cha'rge. opening '42 -is disposedt'adj acent :the end; wall; 441 with the-result that the-sewagera'fter flowingethro'ugh theyfirst flocculator enters the first-settlingbasin at a point adjacent "the; end. wallud lzfh From the latter end wall the sewage flows slowly :through the settlingjbasin'w I 0? toward the:- end wall 45L 7 The edge of saidendwall 45 is .disposed-at'such a'level that it 'formsa weir whereby: thessewage latter itfiows through the; first settling. basin spills into a discharge chaimeLM. Th'eJa'UtBPiSiCOHHECtBd to; and located outwards; Ofyjthe: up ezaportion of thew-end wall- 45; Astthe sewageafiows, through the first settling basinal ll; the-.floc struoture settles tolthe bottomlofcthe basin-in the form ot-sludge. The:sludgegravitatesrto thaapex portionof the ,of thesecondr flocculato'r 12.2.

bottom-wa1l-46- of the first settling-basin and-.is discharged into the ozonatingtank I-I via the valve controlled and pump eguipped pipe l8; to become a;componentof :thecoagulatingand flocculating mediums If desired; "an/able controlled branch pipe; 48 may be connected to the pipe: I 8 in aorderto perm-it the first-settling-basin lfl to be=-drained-- for cieaning; purposesonto discharge thessludge, or any-partthereot when it is desired to .operate the apparatus eitherwiththe sludge as -the= flocculating mediumor with only a part oithesludge assuchcomponent." Preferably the first settling basin l 0 is 1 of 'such capacityas .to cause a vretention period :for. the sewage oft-from 1, /2 hours :to 3; hours" In practice itrhas: been found that in such time substantially all r the flocculatedsubstance-or sludge settles to the bottom of-the basin; a When the sewage; aftertraversingthe firstsettling basin I 0; entersthedis-1- chargechannel 41 it is. free fromor: rid of substantially all, suspended particles therein "and is practically colorless; As shown in the-drawing, the: bottom wall.,35-of the firstflocculator 9 is downwardly inclined: and forms a continuation of the adjacent side, portion of-the hottom-wa1=l 46 of :the first settling basinl 1.- The-.lowerportion ofi the inner sidewall 34- ofathe first" flocculator is-spaced from the. adjacent portion of the loot-. tom wall- 35 and embodiesarr extension which is downwardly inclinedim conformity with, and is spacedv from; thenadjacent lportionof. the -'bot-, tom. wall 46 iof -the-firstisettlingz basin and defines withlsuchportion-a downwardly-andrinwardly:ine clined channel 5B:which.-1eadsfrom the rbottom ofithe' first flocculator 9 to the: apex portion. of the .bottom wall 450i the first settling-basin, and permitslthe sludge or :fioc structure that settles to. the bottomof- :the first-fiocculator-fi to .gravitate to;the apex-.portionzof the bottom: wall 48 on thefirst-settling; basin from which it may; be

removed as; above described.-: It is contemplated that other appropriate means may be utilized for discharginginto the firstsettling basin any sludge which settles at the bottom ofthe first-fiocculator. although. the. channel. 50' effects communication betweenlthe first 'fiocculator- 9 and the first-settling lbasinul 0 substantially all of-thelsewage-with the coagulating-andflocculating mediumitherein flows through the first fiocculator-9t-and'enters :the first settling basin I 0-- via: therdischarge openingllZLwhich, as heretofore pointed out; is located. adjacenttheiendtwall 44 ref-"the first-settlihgbasin.

The lozonating towerl l is located outwards-and extends lengthwise ofthe side'wall'43 of the first settling basin-l 0. It is comparatively narrow as shown .inithe drawing, andccmprises -:a pair :of laterally. spaced sidewalls}; I a pair of: endiwalls 52-;ancL 53 ,anda' bottomaw-all- 54. The discharge end of the channel leads; to, and communicates with, theozonatingatoweri Hat a point'adjacent the J end ..wall 52 with-- the result that the: efiiuent from thefirst. settling basin' jflows longitudinally through the ozonatingqtowerrfrom the. end' wall 52-1 toth-e end. wall- 53;, or it maybe led otherwise through the towento. promote :efi ective 'ozonation. Atapoint adjacent the-end wall 5-3 .theozonating tower- I Iv is; provided; with: aQdischargeE'duCt :5 5 which leads iromathe tower? to the' -receivingj end In'addition to: the parts;heretofore-mentionedcthesozonatingzltower l 1 contains a-horizontaljseriesz of laterally spaced diffusers 56.. These cliff11sers-arerlocate'd:directly over. the .rbottomi wall: 54+ of. ithe :ozonating2 tower. 7 5

They are rlikeor similar to theydifiusersszll in the 9' ozonating tank- I! oftheunit sand are connected to a header type pipe which ,extends'length wise over the outer bottom wall 55 and is .connected' by a pipe 58 -110 receive ozonous and electrified air from the ozone 'generator 2].

,When the apparatus is in operation the portion voflihe ozonousand'electrified air that is supplied tolthe header type pipe 51,-flows from such pipe into the zdifi'users 55 and is caused to enter the sewage in the ozonating tower in the form of small -or minute bubbles. The latter fiow upwards'through thesewage in the tower and serve to purify and deodorize the sewage. They also serve to reactivate by oxidation any residual or spent coagulating and fiocculatingmedium to the point where the medium tends to coagulate, fiocculate and precipitateany residual particles in suspension in the sewage. The sewage as it enters the ozonating tower from the channel A l is practically colorless, as previously pointed out.

However,.as it flows through the tower and is contacted by the bubbles of ozoncus and electrified air it becomescloudy. The cloudiness of marginal portion of the end wall 10 of the second settling basin is disposedfata lower level than the-upper portion of the end wall 69 andfforms a weir. over which the sewage spills into an maybe, discharged. 'As shown in the drawings,

the sewage in the ozonating tower is attributable tothe fact that the residual coagulant in the sew- .age is reactivated by the ozonous and electrified air. and hence efiects coagulation, flocculation and precipitation of any residual suspended organic or inorganic particles-or substances. in the sewage. The size, capacity and shapeof the ozonating tower H are preferablysuch that the sewage flows through, and is subject to contact with, theozonous and electrified air in thetower for a period of between 3'to 10 minutes.

The second fiocculator I2 is located adjacent to and extends lengthwise of the side wall of the ozonating tower II that is farther from the first settling basin H) and is thesame in design and cohstruction as the first fiocculator 9. It functions in the same manner as the first fiocculator. As its component parts the second fiocculator 12 comprises laterallyspaced outer and inner side walls 59 and-59, end walls BI and 62, a bottom wall 63, a series of battles 6'4 and a series of coactingbafilesBE. The side, end and bottom walls of the second'fiocculator l2 define a horizontally elongatedchannel E5through which the sewage flows after passing through the ozonating :tower II. The discharge, duct 55 which leads from the discharge end of the ozonating tower II is con- 'nected to the "outer side wall 59 of the second fiocculator and.dischargesinto the inlet or receiving end of such, fiocculator. During fiow through thesecondfiocculator of the ozonated or reactivated coagulating andfiocculating medium in the sewage it coagulatesand flocculates whatever residual particles are in suspension in the sewage. The size, capacity and shape of the secondfiocculator are such that it takes the sew-1 age approximately between 15 to minutes to 1lowtherethrough. The discharge end of the second, flocculator embodies an outlet openingBi andjthisis formed in the inner side wall 60.

p The second settling basin [3 is similar to, and functions in the same manner as, the first settling basin II]. It comprises a side wall 68, a pair of end walls 69 and HI and a downwardly tapered hopper-like bottom wall I I. The discharge opening 6! at the dischargeend of the second fiocculator. l2 communicates with the second settling basin 13 at a point adjacent the endwall 69 as shown in Figure l of the drawing. During flow of the sewage through the settling basin the coagulated and fiocculated substances settle onto the apex portions of the, bottom wall H. 'Ihe sewage, upon entry' into v is clarified and due to and entirely incfiensive.

the bottom wall 63 of the second fiocculator I2. is.

downwardly and inwardly inclined and forms a continuation of the adjacent portion'of the botto'rftwall "H or the. second settling basin, and the bottom marginal portion of the inner side wall 68 of thesecond .fiocculator'is provided with an extension 14 which defines .With the' adjacent portion oflthe bottom wall of the second settling basin a channel" 15 wherebyv all coa'gulat'ed and fiocculated substances that tend; tov settle toward the bottom of the second fiocculatorarepermitted togravita'te into the apex portion of thebottom wall of the second settling basin. Other appropriate. means may be utilized for discharging into .the second settling basin any sludge which settlesfat'thebottom' of the second fiocculator.

. fTheeflluent'duct" I4 is connected, to, and leads from, the central portion of '12 and serves to discharge the efiiuent channel the treated, clarified and purified sewage to any desiredpoint. The the effluent channel ,12, to the appearance of drinking water treatmentin the apparatus is odorless dischargedfrom the second settling basin may, if desired, be led back intothe influentraw sewage'bywayi'ofja valve controlled pump equipped pipe 15. Such sludge becomes a part of the sludge that is ultimately recovered from" the first settling basin. ,As

The sludge which is shown in the draw ng the pipe. l fi leads to misingchamber 1,1,.

The operation of theapparatus is as'iollows:

, Thev sewageto be treated flows successively. through the infiuent duct 5, the unit 5, the mixsettlingbasin I0, the ozonating tower "H the second fiocculator I2, the second settlingjbasin I3 and theefiiuent duct l4. During fiow ofthe sewage'fthroughthe mixingjchamber 1 itis in- .timatelyfmixed with the coagulating and flocculating medium which is produced by the unit 8 and isjin the form of an acidifiediferrousjsul phate solution (alone orin combination with recovered sludge), that is activated by way of ozono'us andpelectrified air. During flow of the sewage through the first fiocculator9the coaguletting and fiocc'ulating medium' coagulatesland fiocculates the suspended particles in the sewage.

Becauseof the fact that the sewage is subjected to slow or non-violent agitation in' the first fiocculator there is'a pronounced tendencyforgthe fusers 56. During fiow of the sewage through the second fiocculatorthe reactivated coagulating ace-ate? 7 1-1 a and" flocculatingmedium serves *to coagiflateahd iflocculate anyzresidual particles in "suspension and these precipitate and gravitate to the bottom roithe'secondsettling basin during passageof'the sewage; through "such basin. 1 In starting the apparatus Ztheref is,::of course, no :sludge available 'fonadmixturewith'the acidified-ferrous sulphate solution in'the pzonatingtank 'I hand; therefore, lduriugfjthe early stages. of operation of :the ap- .paratll. ,:the coagulating and fiocculatin medium. consists. only of ozonated' and acidifiedfferjrous sulphate solution. 7 After the-apparatus is-in operational suffiicent period of time for sludge to collectiin the. bottom oflthe "firstsettling basin 10 such sludge isrintroduced' via-the valvecontrolled pump equipped r pipe l 8 .into 'thepzonatiine tank 111. where. it is ozonated for purposes-of v-b.eco ming, a component of thecoagulating-and lfloccula'timg;v medium. 'The sludge is preferably utilized asa component of such medium because it has, great aflinityrfor :the ozonous and electrifiedcainlaiid .combined with theozonated and acidified 'jerrousfls lphate. solutionw-produces a medium. well. capable of "producing :coagulation sandiflocculation of. the particlesin'suspension "in .the .raw sewa e, and reduces materially "the amountfofozon'ated and acidified ferrous-sul- ,phatefsolution. c As stated heretoforefthe method will; however, function to produce satisfactory resultsregardlessoi whetherthe coagulatingand Iflocc'ulating medium includes as'a component the ozonatedandacidified sludge. 7 V

Q'IIheQherein described apparatus and 'method effectively and fiijcien'tly fulfill their; intended purpose and serve or operate .to effect at a'comparatively. -low. cost treatment, .clarificationand -purification of ..a pollutedi liquid with. particles suspended therein. practiceit has bBBIITfOHIId that (when the present apparatus 7 and .method v'arelusedin connectionlwjiththe treatment; of sewage the percentage of reduction the'biochemi- ,ca1 oxygen demand (B."O."D.) 'ofrthejs ewagefis high as can beobtained under the' best conditions -by heretofore employed. "apparat s and Jmethods. V a 1 v v ZWhereas other apparatusand, method .have'j been described in connection with the 1 treatment of -sewage' itcis' c tol be understood thati'theyj may be -efieetirelyiutilized in connection with thetreat- -ment 10f any other liquid having; particles sus pended therein, notionlyjfortpurificationjof the liquid' but also l'for jrecovery of such j "suspended -.matter '.for realization of the commercial value V thereof. It is also to be .understoodithat the in- V vehtionis notltoibe restricted ,to the fdetailsset flith..'since lfthese' may "be modified :with'injfthe scope of theappen'ded, claims Without departing from thel-fspirit and scope of theiinventionl W V iii-laying cthus described thei'invention whatiI claims as new .and 'jde'sire ,tQ secure by Letters LPatentisL w l. 7 A u f 1. ."An. apparatus fiorftreatin liquid 1 willhspar- .ticlessuspendedthereingclomprisin means-formiingja'chamber adahtdlto'ihave the'jliquid' to, be treated flow therethrough,'means' for introducing r into the. chamberi'ior admixture with the liquid therein a preformed'liquid"medium in' theform For" an ozonated coagulating and flocculating 'metallie salt solution, in orderto 'efiect coagufllation'.andjfiocculationof thezparticles suspended injithe'jliquid, a :settling basin of comparatively ;;large ;capacity arranged-and adapted" to receive the liquid a'fter'flow thereof'through thelchamber and'.to have it flow so slowly 'therethroughthat substantially the majority 'of the coagulatecl and 12 'flocculated particles settles'out, a tower connected to receiye thefliquidfrom the settling'basin and to have-theliquidTflow'therethrough, means in the lower portion-of the I tower for introducing 'intothe liquid thereimnumerous minute bubbles ofozonou s and electrifiedau inorder to reacti- -vate*the -residual metallicsalt-component of the 'mediumand' cause it to coagulate and *fiocculate the residual suspended "particles in the liquid, and-means for 'removing'f romtheliquid after passage thereof through-the-tower the coagulated and flocculated residua1 particles suspended therein;

2. -'-An-- apparatus' fortreating liquid with parti- -cles=suspended-therein, comprising means forminga chamber adapted to -have the liquidto be treated flow therethrough' means for introduc- "ing" into *"thel chamber for f admixture with l the liquid-thereina-preformed liquid" medium in the form-of a-n ozonated-coagulatingand flocculating --metallicsalt solution' in' orderto: effect coagula- 'tion andflocculation ofzthe-"particles suspended -in the=;li quid, -asettling-*basimof comparatively large capacity-arranged and adapted 'togreceive the liquid after flow thereof jthrough the cham- =-ber arid t0- have it -fiowso slowly therethrough that substantia'lly I themajority -of1the coagulated and 'Eflocculated-particles settles out and *forms sludgefa' tower" connected to receive the liquid 30 'therethrough,f rneans the lower portion ofthe "tower for {introducing {-into the liquid therein from-thesettling basin-and tohave the liquid flow numerousminute'bubbles of "ozonousjand electrified air in order' to reactivate the-residualmetallic salt component of: the medium'and cause" it to coagulate-andflocculate' the :residual j suspended particles in the liquid,= '-means for removingtfrom the liquidafter-passage thereof through the tower-the 'coagula-ted and fiocculatedresidual --moving the -=sludge from the= settling basin and -mixing -it with the liquid medium prior to introduction -ofthe latter into saidchamber.

particles suspendedtherein, and means for re- '3. A-n apparatus fortreating liquid with particles suspended therein; comprising means form- :ingachamber adapted to have the liquid to "be treated fiowtherethrough, mean for introducing 'intothe' chamber for' admixture with the liquid therein aliquid *mediumin the formof 'an oz'onated coagulating-and fiocculating metallic salt solution, in order -to-efiect-coagulation and "flocculation "of the particles "suspended in the liquid a-settling basi-nofcomparatively large capacityarranged and adapted to receive the "liquid have itfiowso slowly therethroughthat substantially the-majority of: the coagulatedra'nd floccu- -lated particles settles out and forms sludge, a "tower connected to receivet'the: liquid from the after 'flowthereof --thr0.ugh therchamber and to settl-ing basin and-tdhave' the liquid "flow; there- "throughj-means"the. lower portion of the tower for-introducinginto*thetliquid therein numerous minutef bubblesofsozonous'and electrified air in I order" toreactivate the" metallic salt. component of fthetliquid mediumand cause 'itflto coagulate andfiiocculate the residual suspended. particles in the liquidpmeans fort-removing fr0m..the liquid agulated and l af-ter passagethereofthroughthe tower the co- 7 fiocculated*'residua1 particles suspended therein, meansffor removing the sludge fromjhe-settling basin; and means for lozonating theremovedysludge and mixingit with said liquid medium prior "to introduction :of the. latter into 'the chamber.

'4. An apparatus"for treating'liquid part1- cles suspended therein, comprising means forming a chamber adapted to have the liquid to be treated flow therethrough, means for introducing into the chamber for admixture with the liquid therein a liquid medium in the form of an ozonated and acidified ferrous sulphate solution in order to coagulate and fiocculate the suspended particles in the liquid, a first settling basin of comparatively large area arranged and adapted to receive the liquid after flow thereof through thechamber and to have it flow so'slowly-therethrough that substantially the majority of the coagulated andflocculated particles settles out and fornis sludge, a tower connected to-receive the liquid after passage thereof through the settling basin and to have the liquid flow there through, means in the lower portion of the tower for introducing into the, liquid in said tower numerous minute bubbles of oz onous and electrified air in order to reactivate the residual fe'r- 'rous sulphate component of the "medium and eftherethrough; means in the lower 'tling basin, and means 14 the settling basin and to have the liquid flow portion or the tower for introducinginto the liquid in said tower numerous minute bubbles of ozonous' and electrified air in order'to reactivate the residual ferrous sulphate component of the medium and effect coagulation and flocculation ofthe residual suspended particles in the liquid, a second settli'ng basin adapted to receive the liquid after flow thereof through the tower andto have it "flow so slowly therethrough that the'coagulated and flocculated residual particles settle out,

means for-removing the sludge from the first setfor ozonating'the removed sludge "and mixing it with said liquid medium prior to introduction of the latter into-said chame ber;

fect coagulation and flocculation of the residual ing into the chamber for admixture with the liquid therein a liquid medium in the form of an ozonated and acidified ferrous sulphate solution inorder to coagulate andfiocoulate the suspended particles in the liquid, a first settling basin of comparatively large area arranged and adapted to receive the liquid after flow thereof through the chamber and to have it flow slowly therethrough thatsubst'antially the majority of the coagulated and 'fiocculated particles settles out and forms sludge, a tower connected to receive the liquid after' passage thereof through the settling basin and to havethe liquid 'fiow therethrough, means in the lower portion of the tower for introducing into the liquid in said tower numerous minute bubbles'of ozonous and electrified air in order to reactivate the residual ferrous sulphate component of the ,medium and effect coagulation and flocculation of the residual sus-- pended particles in the liquid, a second settling basin adapted to receive the liquid after flow thereof through the tower and to have it flow so slowly therethrough that the coagulated and flocculated residual particles settle out, and means for removing the sludge from the first settling basin and introducing it into the liquid medium prior to introduction of the latter into the chamber.

6. An apparatus for treating liquid with particles suspended therein, comprising means forming a chamber adapted to have the liquid to be treated fiow therethrough, means for introducing into the chamber for admixture with the liquid therein a liquid medium in the form of an ozonated and acidified ferrous sulphate solution in order to coagulate and fiocculate the suspended particles in the liquid, a first settling 'basin of comparatively large area arranged and adapted to receive the liquid after flow thereof through the chamber and to have it flow slowly therethrough that substantiallyth majority of the coagulated and fiocculated particles settles out and forms sludge, a tower connected to receive the liquid after passage thereof through mg a chamber adapted treated flow therethrough, means forintroducing into the chamber for admixture'jwith the 7. An apparatus for treating liquid with particles suspended therein, comprising means formto have the liquid to be liquid therein a liquid'medium in the form of an ozonated and acidified ferrous sulphate solution in order to coagulate and fiocculate the suspended particles in the liquid, a first settling basin of comparatively large area arranged and adapted to receive the liquid after flow thereof through the chamber and to have it flow slowly there- "through that substantially the majority of the coagulated and flocculated particles settles out "and forms sludge, a tower connected'to receive the liquid after tling basin and passage thereof through the setto have the-liquid flow therethrough, means in the lower portion of the-tower for introducing into the liquid in said tower numerous minute bubbles of'ozonous and electrified air in order to reactivate the residual ferrous sulphate component of the -medium*-and' effect coagulation and flocculation of the residual suspended particlesin the liquid, a second settling basin adapted'to receive the liquid after flow thereof through the tower and to have it flow so slowly ther'eth'rough that th coagulated and flocculated residual particles settle out, and means for removing'the settled out residual particles and introducing them into said chamber.

8. An apparatus for treating liquid'with particles suspended therein, comprising a tank pro- 50 vided with means for forming therein a coagulating, and fiocculating metallic salt solution, and in addition means for introducing into its lower portion minute bubbles of ozonous and electrified air under pressure in order to ozonate the solution and form it into coagulating and flocculating medium, means forming a mixing chamber, means for introducing the liquid to be treated into the chamber, means for delivering said coagulating and fiocculating medium from the tank into said chamber for admixture with the liquid in order to effect coagulation and flocculation of the suspended particles in the liquid and form them into sludge, and means for removing the sludge from the liquid.

9. An apparatus for treating liquid with particles suspended therein, comprising a tank provided with means for forming therein a coagulating and fiocculating metallic salt solution, and in addition means forintroducing into its lower portion minute bubbles of ozonous and electrified air under pressure in order to ozonate the solution and form it into a coagulating and fio'cculating medium, means forming a mixing chamber, means for introducing the liquid to be treated into the chamber, means for delivering said coagulating andw-flocculating medium from the tank into "said chamber for- .admixturewith the liquidr-in order to :efiect coagulationand flocculation of the suspended particles in the liquid and 'form them into sludge, andrmeans forremoving the sludgefrom the ,liquid and introducing it intoithe tank for iadmixture and ozonation with the solution therein.

710. An apparatus "for treating liquid :Withpartic-les suspendedtherein, comprising a-mixing tank provided with means :ior forming therein a v-ferrous; sulphate solution, and in addition means "for 'introducing into its lower portion nu- ?merous; minute; bubbles; of ozonous and electrified' air rin order :toozonate 'the solution and form-itinto a coagulating and flocculating medium, means forming a chamber adapted to have the-liquid to-betreated fiow therethrough, means for -deliveringrsaid coagulating and fiocculating medium fromthe-tankinto the chamber for ad- -mixture with the liquid therein in order to effect coagulation and flocculation of the suspended particles in said'liquid and form-them into sludge, and means 'for removing the sludge from the liquidafter flow' of the latter through the cham- "ber-.and--.deliveri-ng-it into the'tank-for admixture and ozonation with the solution therein.

- 11.-That improvement in treating liquid with particles suspended thereinwhich comprises in- -troducing intoa ferrous sulphate solution nu- =merous: -minute=bubbles ofozonous and electrified:air-sunder pressurein order to convert the solution: into :a' coagulating and fiocculating liqfluid. medium, then introducingsaidv medium into the iliquid to be treated in order;v to effect coagulation-and flocculation of the-particles therein, andnthen, removing the ,coagulated and floc- Hculated particlesfromrthe-liquid.

12. That! improvement in treating liquid with v.particles suspended therein which comprises introducingjinto an acidified ferrous sulphate so- ;lution ozonous and electrified air-under pressure for such length-of time and'in such amount as to obtain substa-ntially complete saturation of the solution with ozone and form an ozonated and acidified coagulating and -fiocculating 1 mediumpthen introducing the'medium into the liq- .Juid to-betreated in order to effect coagulation and fiocculationof the suspended-particles therein iand then removing theficoagulated andfioc- 4 culated-particles. from-the .liquid.

--13. That-improvement in treating liquid with particles suspended thereinwhichcomprises subjecting-a ferrous sulphatesolution to ozonous and electrified air inorder toiform acoagulat- .ing and fiocculating medium, introducing the -medium into the liquid to be treated in order to efiect coagulationvand flocculation of the suspended particles therein and cause ,such particles to formsludge, and removing the sludge from the liquid and introducing it into said medium ,prior to introduction ofthe latter intosaid liquid.

14. That improvement in treatingliquid with particles suspended therein which comprises/introducing into an acidified ferrous sulphate so lution numerous minute bubbles of ozonated and electrified air in order to convert thelsolution vinto a coagulating .and flocculating medium,flintroducing the medium into the liquid to, be

and introducing itv into the solution While said minute 'bubblesof o'zonous and electrified air are being introduced into it.

JAMES M. DAILY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name v.Date

1,079,569 Leet Nov. 25, 1913 1,222,637 Landreth Apr. 17,1917 1,441,731 Mathis Jan. 9, .1923 1,658,974 De La Porte'et al.' Feb. 14, 1928 1,797,879 Rudolfs Mar.,24,- 1931 1,837,286 'Appenheim Dec; 22, 1931 1,915,240 Putnam June 20, 1933 2,043,458 Windecker'et al. June 9, 1936 2,077 ,498 Streander Apr. 20, 1937 2,101,810 Fischer Dec. 7, 1937 2,128,569 Velz Aug. 30, 1938 2,167,443 Bevan July 25, 1939 2,320,512 Daily June-1, 1943 FOREIGN PATENTS Number Country Date 550 GreatBritain of .1900 

8. AN APPARATUS FOR TREATING LIQUID WITH PARTICLES SUSPENDED THEREIN, COMPRISING A TANK PROVIDED WITH MEANS FOR FORMING THEREIN A COAGULATING AND FLOCCULATING METALLIC SALT SOLUTION, AND IN ADDITION MEANS FOR INTRODUCING INTO ITS LOWER PORTION MINUTE BUBBLES OF OZONOUS AND ELECTRIFIED AIR UNDER PRESSURE IN ORDER TO OZONATE THE SOLUTION AND FORM IT INTO COAGULATING AND FLOCCULATING MEDIUM, MEANS FORMING A MIXING CHAMBER, MEANS FOR INTRODUCING THE LIQUID TO BE TREATED INTO THE CHAMBER, MEANS FOR DELIVERING SAID COAGULATING AND FLOCCULATING MEDIUM FROM THE TANK INTO SAID CHAMBER FOR ADMIXTURE WITH THE LIQUID IN ORDER TO EFFECT COAGULATION AND FLOCCULATION OF THE SUSPENDED PARTICLES IN THE LIQUID AND FORM THEM INTO SLUDGE, AND MEANS FOR REMOVING THE SLUDGE FROM THE LIQUID. 